Philippe Belley

Memorial University of Newfoundland · Department of Earth Sciences

Gem-quality corundum (sapphire) occurs in scapolite-rich calc-silicate rock hosted in marble of the Lake Harbour Group near Kimmirut, southern Baffin Island. A deposit of blue and colorless gem corundum (Beluga occurrence) is compared to a similar calc-silicate pod generally lacking corundum but containing nepheline (Bowhead occurrence) and located...

Samples from 14 spinel occurrences in the Lake Harbour Group (LHG), Baffin Island, Nunavut, Canada, were studied using a combination of petrography, whole rock geochemistry, microprobe analysis, and, where possible, geochronology. Spinel at most occurrences is blue to violet and generally not of gem quality. Two spinel occurrences near Kimmirut con...

Baffin Island's Lake Harbour Group (LHG), a Paleoproterozoic granulite facies metasedimentary sequence rich in carbonates, contains occurrences of the gemstones sapphire (corundum), spinel (including vivid blue, cobalt-enriched spinel), and lapis lazuli (haüyne-bearing rock). Most occurrences of these gem minerals are uniquely metasedimentary (carb...

Consumer-grade camera drones have dramatically improved with regards to affordable cost, camera quality, telemetry capabilities, flight time, and location data. This case study examines the use of a drone camera and geospatial analysis in peridot exploration. Gem-quality olivine (peridot) occurs in peridotite xenoliths in the Chilcotin Group Basalt...

Serendibite, Ca1.93Na0.08Mg2.58Al5.03B1.53Si2.71O20, was recently discovered in a lens of B-rich calc-silicate rock metamorphosed at 6–7 kbar, 650–700 °C in the Central Metasedimentary Belt, Grenville Province. Based on paragenesis and tourmaline composition, which were used to monitor changes in fluid composition, the following stages of mineraliz...

The Blue Arrow and Blue Bear iolite (gem cordierite) claims located in the Thor-Odin dome (near Revelstoke in British Columbia, Canada) are two new examples of iolite occurrences hosted in hydrothermally altered mafic volcanic rocks metamorphosed at upper amphibolite to granulite facies, in which cordierite (XMg = 0.81–0.90) occurs in association w...

Oxy-dravite, ideally Na(Al 2 Mg)(Al 5 Mg)(Si 6 O 18 )(BO 3 ) 3 (OH) 3 (O), was found in a composition near its ideal end-member at the Beluga occurrence, Nunavut territory, Canada. It occurs in retrograde albite–muscovite–corundum–calcite domains in a calc-silicate rock. This uncommon oxy-dravite occurs as dark brown, equant to short-prismatic, idi...

A new, comprehensive approach to characterizing detrital corundum in sediments and placer deposits is outlined and applied to a sample of poorly sorted, mud-supported colluvium rich in rhyolite tuff clasts from the sapphire-producing layer at Gem Mountain Mine, Rock Creek, Montana. High angularity and the predominance of inherited surface features...

The sapphire (corundum) occurrence near Revelstoke, British Columbia, Canada, occurs in the Monashee Complex of the Omineca Belt of the Canadian Cordillera. Corundum occurs in boudins or pod-like zones of restite within a garnet-bearing leucosome. Both zones are peraluminous and contain plagioclase, K-feldspar, and biotite and muscovite as the domi...

This study compares two purple gem spinel samples with regard to trace element chemistry and visible light absorption spectra, and presents the first reported example of a spinel with a saturated purple color caused predominantly by chromium and cobalt. Sample VN, from a placer deposit in the Luc Yen district of Vietnam, exhibited strong saturation...

Serendibite has been recently discovered in the Portage-du-Fort area, Pontiac Regional County Municipality, Quebec. Dark blue, often polysynthetic twinned on {011} and with no cleavage, serendibite crystals occur exclusively in a calc-silicate rock. Fine-grained anhedral serendibite, sometimes poikiloblastic, occurs with aluminous diopside. Less co...